Frozen debris lobe morphology and movement: an overview of eight dynamic features, southern Brooks Range, Alaska
Frozen debris lobes (FDLs) are elongated, lobate permafrost features that mostly move through shear in zones near their bases. We present a comprehensive overview of eight FDLs within the Dalton Highway corridor (southern Brooks Range, Alaska), including their catchment geology and rock strengths, l...
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Copernicus Publications
2016
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fttriple:oai:gotriple.eu:oai:doaj.org/article:bf5e539fc08446ecaff7375f1ab7afc1 2023-05-15T15:46:58+02:00 Frozen debris lobe morphology and movement: an overview of eight dynamic features, southern Brooks Range, Alaska M. M. Darrow N. L. Gyswyt J. M. Simpson R. P. Daanen T. D. Hubbard 2016-05-01 https://doi.org/10.5194/tc-10-977-2016 http://www.the-cryosphere.net/10/977/2016/tc-10-977-2016.pdf https://doaj.org/article/bf5e539fc08446ecaff7375f1ab7afc1 en eng Copernicus Publications 1994-0416 1994-0424 doi:10.5194/tc-10-977-2016 http://www.the-cryosphere.net/10/977/2016/tc-10-977-2016.pdf https://doaj.org/article/bf5e539fc08446ecaff7375f1ab7afc1 undefined The Cryosphere, Vol 10, Iss 3, Pp 977-993 (2016) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2016 fttriple https://doi.org/10.5194/tc-10-977-2016 2023-01-22T19:30:28Z Frozen debris lobes (FDLs) are elongated, lobate permafrost features that mostly move through shear in zones near their bases. We present a comprehensive overview of eight FDLs within the Dalton Highway corridor (southern Brooks Range, Alaska), including their catchment geology and rock strengths, lobe soil characteristics, surface movement measurements collected between 2012 and 2015, and analysis of historic and modern imagery from 1955 to 2014. Field mapping and rock strength data indicate that the metasedimentary and metavolcanic bedrock forming the majority of the lobe catchments has very low to medium strength and is heavily fractured, thus easily contributing to FDL formation. The eight investigated FDLs consist of platy rocks typical of their catchments, organic debris, and an ice-poor soil matrix; massive ice, however, is present within FDLs as infiltration ice, concentrated within cracks open to the surface. Exposure of infiltration ice in retrogressive thaw slumps (RTSs) and associated debris flows leads to increased movement and various stages of destabilization, resulting in morphological differences among the lobes. Analysis of historic imagery indicates that movement of the eight investigated FDLs has been asynchronous over the study period, and since 1955, there has been an overall increase in movement rates of the investigated FDLs. The formation of surface features, such as cracks, scarps, and RTSs, suggests that the increased movement rates correlate to general instability, and even at their current distances, FDLs are impacting infrastructure through increased sediment mobilization. FDL-A is the largest of the investigated FDLs. As of August 2015, FDL-A was 39.2 m from the toe of the Dalton Highway embankment. Based on its current distance and rate of movement, we predict that FDL-A will reach the Dalton Highway alignment by 2023. Article in Journal/Newspaper Brooks Range Ice permafrost The Cryosphere Alaska Unknown The Toe ENVELOPE(-59.167,-59.167,-62.333,-62.333) The Cryosphere 10 3 977 993 |
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Open Polar |
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language |
English |
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geo envir |
spellingShingle |
geo envir M. M. Darrow N. L. Gyswyt J. M. Simpson R. P. Daanen T. D. Hubbard Frozen debris lobe morphology and movement: an overview of eight dynamic features, southern Brooks Range, Alaska |
topic_facet |
geo envir |
description |
Frozen debris lobes (FDLs) are elongated, lobate permafrost features that mostly move through shear in zones near their bases. We present a comprehensive overview of eight FDLs within the Dalton Highway corridor (southern Brooks Range, Alaska), including their catchment geology and rock strengths, lobe soil characteristics, surface movement measurements collected between 2012 and 2015, and analysis of historic and modern imagery from 1955 to 2014. Field mapping and rock strength data indicate that the metasedimentary and metavolcanic bedrock forming the majority of the lobe catchments has very low to medium strength and is heavily fractured, thus easily contributing to FDL formation. The eight investigated FDLs consist of platy rocks typical of their catchments, organic debris, and an ice-poor soil matrix; massive ice, however, is present within FDLs as infiltration ice, concentrated within cracks open to the surface. Exposure of infiltration ice in retrogressive thaw slumps (RTSs) and associated debris flows leads to increased movement and various stages of destabilization, resulting in morphological differences among the lobes. Analysis of historic imagery indicates that movement of the eight investigated FDLs has been asynchronous over the study period, and since 1955, there has been an overall increase in movement rates of the investigated FDLs. The formation of surface features, such as cracks, scarps, and RTSs, suggests that the increased movement rates correlate to general instability, and even at their current distances, FDLs are impacting infrastructure through increased sediment mobilization. FDL-A is the largest of the investigated FDLs. As of August 2015, FDL-A was 39.2 m from the toe of the Dalton Highway embankment. Based on its current distance and rate of movement, we predict that FDL-A will reach the Dalton Highway alignment by 2023. |
format |
Article in Journal/Newspaper |
author |
M. M. Darrow N. L. Gyswyt J. M. Simpson R. P. Daanen T. D. Hubbard |
author_facet |
M. M. Darrow N. L. Gyswyt J. M. Simpson R. P. Daanen T. D. Hubbard |
author_sort |
M. M. Darrow |
title |
Frozen debris lobe morphology and movement: an overview of eight dynamic features, southern Brooks Range, Alaska |
title_short |
Frozen debris lobe morphology and movement: an overview of eight dynamic features, southern Brooks Range, Alaska |
title_full |
Frozen debris lobe morphology and movement: an overview of eight dynamic features, southern Brooks Range, Alaska |
title_fullStr |
Frozen debris lobe morphology and movement: an overview of eight dynamic features, southern Brooks Range, Alaska |
title_full_unstemmed |
Frozen debris lobe morphology and movement: an overview of eight dynamic features, southern Brooks Range, Alaska |
title_sort |
frozen debris lobe morphology and movement: an overview of eight dynamic features, southern brooks range, alaska |
publisher |
Copernicus Publications |
publishDate |
2016 |
url |
https://doi.org/10.5194/tc-10-977-2016 http://www.the-cryosphere.net/10/977/2016/tc-10-977-2016.pdf https://doaj.org/article/bf5e539fc08446ecaff7375f1ab7afc1 |
long_lat |
ENVELOPE(-59.167,-59.167,-62.333,-62.333) |
geographic |
The Toe |
geographic_facet |
The Toe |
genre |
Brooks Range Ice permafrost The Cryosphere Alaska |
genre_facet |
Brooks Range Ice permafrost The Cryosphere Alaska |
op_source |
The Cryosphere, Vol 10, Iss 3, Pp 977-993 (2016) |
op_relation |
1994-0416 1994-0424 doi:10.5194/tc-10-977-2016 http://www.the-cryosphere.net/10/977/2016/tc-10-977-2016.pdf https://doaj.org/article/bf5e539fc08446ecaff7375f1ab7afc1 |
op_rights |
undefined |
op_doi |
https://doi.org/10.5194/tc-10-977-2016 |
container_title |
The Cryosphere |
container_volume |
10 |
container_issue |
3 |
container_start_page |
977 |
op_container_end_page |
993 |
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1766381776632020992 |